HackMD
Commonly used and basic commands in SAC
Learning resources
https://web.mst.edu/~sgao/manuals/sac_manual.pdf
http://geophysics.eas.gatech.edu/people/zpeng/Teaching/Sac_Tutorial_2006/
https://moodle.glg.miamioh.edu/brudzimr/tutorials/SAC/
https://seisman.github.io/SAC_Docs_zh/
https://ds.iris.edu/files/sac-manual/manual/tutorial.html
Installation
Please refer to installation tutorial
Read, sort, and plot SAC files
Read files
r *.SAC read all file end with .SAC
r more read more
Rearrange
sort x sort by x (attributes in sac file)
sort distance sort by distance
sort a sort by "a" marker
Parser
rtr remove trend
rmean remove mean
int intergrate onece (積分) acc.-> vel.->disp.
dif differentiate (微分) disp.-> vel-> acc.
cut 10 50 cut o+10 o+50 cut the data from 10 to 50 (values in x axis)
r *.sac read the files that need to be cut after cut command
Display
qdp off turn off quick dirty plot, for finer resolution
xlim t1 -5 t3 +50 show range of x axis from t1-5 to t3+50 (command before ppk or p)
xlim o -10 +20 show range from o-10 to o+20
Plot
p plot by default (one file on one page)
p1 plot all files, which has been read, in 1 page
Filter waveforms
bp band pass
lp,hp low pass and high pass
bp n 4 p 2 c 0.02 0.08
n 4 : channel
p 2 : pole
c 0.02 0.08: frequecny range (Hz)
Mark time on waveforms
ppk p 3 m on ppk -> picking mode; p 3 -> one page 3 files; m on -> makeall on (mark all file at the same time)
ppk p 4 picking mode, show 4 files, mark one by one
a,t1…t5 markers
n next page
b back to the last one page
Use mouse to pick two time points for zooming in
x zoom out
k temporally quit
wh write all the change during this round; save the header
q or quit exit (no change will be made and exit)
Write files
w over overwrite the file that is in read now with the same file name
w newname.SAC write/save as a newfile.SAC
w append .bp write as a new file, using original name append with ".bp"
List SAC headers
lh list all headers after read files
saclst kztime kzdate stlo stla stel delta a t1 o f *
list noted headers from file(f) *
saclst evlo evla gcarc kzname f *| sort -nk2 combined with sorting command in linux, sort the second column (i.e., evlo here) -r list reversely
For SAC header variables, please check:
https://ds.iris.edu/files/sac-manual/manual/file_format.html
Write header in SAC files
chhdr
Advanced commands
- Convert data between SAC binary and ASCII files
- Write macro file for batch processing: macro *.m
- generate function
fungenorfggenerate function
FG IMPULSE NPTS 100 DELTA 0.1
fft
plotsp or psp plot spectrum psp am plot amplitude
convolve do convolution with the first file
correlate do cross correlation wtih the first file
Plot SAC with GMT
map view plotting
seismogram and profiles
TauP: travel time calculation
http://geophysics.eas.gatech.edu/people/zpeng/Teaching/EAS8803_S08/ttime/
taup_time -mod prem -h 200 -ph S,P -deg 57.4
SAC> syn
SAC> ppk p 5 m on
SAC> sss
Signal Stacking Subprocess.
SAC/SSS> prs
SAC/SSS> hp cor 1
